1. Technical Field
The present invention generally relates to microelectronic packaging. More particularly, the present invention relates to tools employed to interconnect semiconductor chip packaging structures to semiconductor packaging substrates. Even more particularly, the present invention relates to apparatuses employed to solder bond a plurality of microelectronic leads to their respective contact pads.
2. Background Information
As is well known, soldering represents a common technique employed in numerous joining applications in microelectronics. In accordance with these well-known soldering techniques, flexible circuit carriers are widely used in the design of microelectronic packages to connect various microelectronic packages and devices to one another. For instance, a flexible circuit carrier may be used to interconnect a semiconductor chip packaging structure, such as a multi-chip module, and a semiconductor packaging substrate, such as a printed circuit board.
A problem associated with the design of microelectronic packages is the requirement of providing sound electrical connections between a relatively large number of extremely small conductive leads, i.e., signal, ground, and power conductors, and their respective contact locations. These contact locations, i.e., contact pads, may be applied to a semiconductor chip or other circuit location in a wide variety of configurations. In the microelectronics industry, the precise alignment of a plurality of conductive leads on one semiconductor device to an associated plurality of contact pads on another semiconductor device presents a significant problem. Often, in order to achieve the precise alignment required between the miniature conductive leads and their respective contact pads, sophisticated and expensive alignment systems are necessary. Such systems typically are programmed to achieve extremely close alignment tolerances.
Furthermore, it is often necessary to force the leads, once properly aligned, into contact with their respective contact locations. However, forcing a large plurality of microelectronic conductive leads into contact with a like plurality of contact pads requires a tool which can be precisely aligned so that the leads can be properly displaced to make contact with their associated contact locations. Another device is also needed to heat the contact pads to a temperature sufficient to melt the solid solder thereon so that solder joints can be formed.
As will be disclosed herein, the present invention defines an apparatus and method of using a castellated nozzle for forming sound electrical connections between a semiconductor chip packaging structure, such as a multi-chip module, and a packaging substrate, such as a printed circuit board, without the need for a sophisticated alignment system. These sound electrical connections are achieved notwithstanding the need to force a plurality of leads into contact with their respective contact locations. As will be further defined, such connections can be achieved by soldering. Moreover, the apparatus and method as described herein permits the fluxless solder bonding of conductive leads to their associated contact pads.
The present invention provides a significant improvement over currently known microelectronic soldering devices which effect electrical connections in miniaturized electronic packages and is applicable to tape automated bonding (TAB) technology. The apparatus as defined herein assures strong electrical connections between extremely small microelectronic circuit elements. The apparatus is relatively simple to use, and can be adapted to mass production techniques, thus reducing the overall cost of the final package structure.
Thus, a need exists for an apparatus which simplifies soldering and connection of a plurality of miniaturized microelectronic elements. The structure and method of use of the present invention contains a solution to the aforementioned problems. As defined below, the present invention provides a significant improvement over currently known soldering techniques for performing electrical connections in miniaturized electronic packages.